1. Field of the Invention
The present invention relates to fixing devices, more particularly to a fixing device for use in an image forming apparatus.
2. Description of Related Art
As an invention relevant to a conventional fixing device, for example, a fixing device described in Japanese Patent Laid-Open Publication No. 2012-103612 is known. FIG. 5 is a configuration diagram of the fixing device 500 described in Japanese Patent Laid-Open Publication No. 2012-103612.
The fixing device 500 includes a fixing roller 502, a heating roller 504, a fixing belt 506, a halogen heater 508, a reflective member 510, and a pressure roller 512. The fixing belt 506 is stretched between the fixing roller 502 and the pressure roller 504. The halogen heater 508 is provided in the heating roller 504 in order to heat the fixing belt 506 through the heating roller 504. The reflective member 510 faces a portion of the fixing belt 506 that is in contact with the heating roller 504, so that radiation heat of the fixing belt 506 is reflected back toward the fixing belt 506. There is a nip formed by the pressure roller 512 exerting pressure upon a portion of the fixing roller 502 that is in contact with the fixing belt 506.
Incidentally, the portion of the fixing belt 506 that has been heated by the heating roller 504 is moved to the nip by the rotation of the fixing roller 502 and the heating roller 504. Then, the heated portion of the fixing belt 506 heats a printing medium passing through the nip. However, after the portion of the fixing belt 506 that has been heated by the heating roller 504 leaves the heating roller 504, the heated portion of the fixing belt 506 does not continue to be heated, and therefore, simply radiates heat until it arrives at the nip. Accordingly, during the period after leaving from the heating roller 504 until the arrival at the nip, the temperature of the fixing belt 506 decreases, resulting in heat loss.